As Barry begins to relive the previous day, Dr. Wells realizes what happened and warns Barry not to change any event for fear that he will create a bigger problem as the universe balances itself. Barry does not listen and instead captures Mark Mardon before he can kidnap Joe. Meanwhile, Leonard Snart and Mick Rory return to Central City. Leonard sends his sister Lisa after Cisco, whom they force to rebuild the cold and heat guns, and a third gun for Lisa that turns people into gold, under threat that they will kill Cisco's brother. Barry realizes that Dr. Wells was right, and his actions have resulted in Cisco's kidnapping and Iris rejecting his romantic advances. Cisco returns and reveals that Leonard tortured his brother until Cisco revealed the Flash's true identity. Barry goes after the Snarts, and the two develop an uneasy truce: Snart will not reveal Barry's identity, will no longer kill innocent people, and stay away from Barry's friends in exchange for Barry not locking him away in the particle accelerator. The Reverse-Flash kills a local reporter and destroys evidence linking Dr. Wells to the death of Simon Stagg. The reporter's vanishing causes Barry to think Joe might be right about Dr. Wells.

Mark Mardon, a.k.a. The Weather Wizard (guest star Liam McIntyre) appears in Central City intent on avenging his brother Clyde’s death, and sets his sights on Joe (Jesse L. Martin), who shot Clyde. When Mardon attacks Joe and Barry (Grant Gustin), Barry is able to super-speed them to safety but Mardon gets away. Barry warns Joe not to go after a meta-human alone but Joe doesn’t listen and ends up in grave danger. Meanwhile, Cisco (Carlos Valdes) looks into the night the team captured the Reverse Flash and realizes something doesn’t add up and begins to wonder whether Joe was right about Dr. Wells (Tom Cavanagh). Barry and Linda (guest star Malese Jow) end up on an awkward double date with Eddie (Rick Cosnett) and Iris (Candice Patton). Thor Freudenthal directed the episode written by Todd Helbing & Aaron Helbing.

Barry and Caitlin investigate the explosion and find Ronnie and Dr. Stein have separated. General Eiling investigates the crater left by Ronnie and Stein's explosion, and realizes that "Firestorm" has separated. Joe shows Barry the images from the night his mother was killed, and Barry learns that a future version of himself was there trying to save his mother. Barry talks to Dr. Stein and learns about the possibility of time travel. Dr. Wells visits General Eiling, who reveals that he knows Barry is the Flash and that he wants the F.I.R.E.S.T.O.R.M. project. Dr. Wells gives up Dr. Stein, who is tortured by Eiling until Ronnie shows to save him. Ronnie and Dr. Stein are forced to reunite to survive Eiling's military onslaught. Merging properly this time, Ronnie and Dr. Stein work together to control the Firestorm Matrix within them, gaining enough control to be able to merge and separate on command. The pair decide to leave Central City to stay ahead of Eiling and learn more about their new powers. The Reverse-Flash kidnaps Eiling and brings him to the sewers. He reveals himself to be Dr. Wells, and allows Grodd, who is displaying psychic abilities, to drag Eiling deeper into the sewer.

The Flash (Grant Gustin) faces a new meta-human named Tony (guest star Greg Finley, “Star-Crossed,” “Secret Life of the American Teenager”), who can turn himself into girded steel at will. While Dr. Wells (Tom Cavanagh) and Caitlin (Danielle Panabaker) are concerned about Barry’s safety, Cisco (Carlos Valdes) comes up with a plan to take Tony down. Meanwhile, Iris’s (Candice Patton) blog on The Flash gets her into trouble, and Eddie (Rick Cosnett) witnesses Tony’s abilities firsthand and begins to ask questions that Joe (Jesse L. Martin) doesn’t want answered. Joe asks Dr. Wells to help him solve Nora Allen’s murder. Millicent Shelton directed the episode written by Jaime Paglia & Chris Rafferty.

Dr. Wells returns to his secret room, where it is revealed that he has been documenting Barry's growing abilities, and using his computer to look at events in the future. Barry arrives at a crime scene where the victim was murdered via electrocution, and charred beyond all recognition, suggesting a metahuman was involved. While investigating the victims identity, the team identifies a power drain in the city. When Barry arrives, he is attacked by Farooq Gibran, a man who has the ability to siphon electrical energy. The attack drains Barry of his speed, and when Wells checks his secret computer it reveals that there are no references to Barry or "The Flash" in the future, and thus the timeline is in danger of temporal paradox. Wells believes that Barry's body just needs an electrical jumpstart, and Farooq arrives at the lab while the team is attempting to help Barry.

As Barry works on improving his speed through various training exercises, Leonard Snart returns to Central City with the freeze gun and a new partner, Mick Rory, to set a trap for the Flash. Barry discovers his plan, and agrees with Dr. Wells to not engage Snart in the hope that he goes away and no one gets hurt like the last time. When the Flash fails to show, Snart and Rory, who now has a gun that can emit absolute hot temperatures, kidnap Caitlin to force Barry out of hiding. Cisco and Barry realize that if they can get Snart and Rory to cross the streams of their respective weapons it will cancel out the effects. The Flash meets Snart and Rory in the middle of a city for a showdown, exposing himself to the media. After multiple failed attempts, Barry eventually gets them to cross the streams with Eddie's help, successfully damaging the weapons and disabling the criminal pair. While in transport to Iron Heights Prison, Snart and Rory are broken out by Snart's sister. Meanwhile, Caitlin investigates the cause of Ronnie's transformation.

The team attempts to track Ronnie's whereabouts after he injures a scientist. Knowing that Dr. Martin Stein is in control of Ronnie's body, they use his wife to talk Stein/Ronnie into coming back to the lab for testing. Meanwhile, Joe enlists Cisco's help to identify who murdered Barry's mother. Cisco discovers an old mirror left in the former Allen home that captured images from the night of the murder, and Joe finds blood from two people behind some new wallpaper, one of whom was likely the killer. Joe asks Cisco to compare the blood to Dr. Wells', but Cisco refuses to believe Dr. Wells is involved. Dr. Wells discovers that Ronnie and Dr. Stein's atoms are in conflict, and if it continues they will become nuclear. Dr. Wells determines that the tachyon device recharging his speed could be converted to a quantum splicer to stabilize Ronnie's body and separate the two personalities. Dr. Snow uses the device; Ronnie's body still goes nuclear, but safely away from the city. The explosion alerts General Eiling, who orders a team to recover F.I.R.E.S.T.O.R.M. Cisco runs the blood samples and informs Joe that while neither is from Dr. Wells, one is from an adult Barry.

Caitlin (Danielle Panabaker) decides that she and Barry (Grant Gustin) need to move on from Ronnie (guest star Robbie Amell) and Iris (Candice Patton) and find new loves so she takes him for a night out at the local karaoke bar. Caitlin doesn‘t have any luck making a love connection but Barry meets Linda Park (guest star Malese Jow), a sports reporter for the Central City Picture News, and asks her out on a date. When Barry tells Iris he has a date, Iris is surprised by her reaction. Meanwhile, Cisco (Carlos Ramon) considers Hartley‘s (guest star Andy Mientus) dangerous offer and the team searches for Shawna (guest star Britne Oldford), a meta-human with teleportation powers, who just busted her boyfriend Clay (guest star Micah Parker) out of Iron Heights. When Henry (guest star John Wesley Shipps) snoops around in an attempt to help Joe (Jesse L. Martin) and Barry solve the crime, he ends up in the infirmary after getting roughed up by inmates.

While home, Dr. Wells receives a threatening call from an unidentified person before having to use super speed to move out of the way of his glass ceiling shattering around him. Wells informs Barry and the team that the caller was Hartley Rathaway, a former protégé. Hartley begins attacking his family's business with sonic blasts, and when Barry arrives to stop him Hartley reveals that he knows the secret Dr. Wells is hiding. Dr. Wells reveals that Hartley warned him that the particle accelerator could explode ahead of time, but Wells chose to risk it for the potential rewards. Cisco discovers that Hartley intentionally got caught so he steal information from S.T.A.R. Labs' computer that would allow him to identify the frequency of Barry's molecules so he can kill him. Barry triggers a trap set by Hartley, which starts shredding Barry's organs. Dr. Wells taps into a satellite and sends an alternative frequency to disable Hartley's weapons. Later, Joe has Eddie start an investigation into Dr. Wells. Hartley, imprisoned back in the particle accelerator, reveals to Cisco that he knows where Ronnie is and how to save him. In his secret room, Dr. Wells uses the tachyon technology to temporarily recharge his speed force energy.

After a bomb goes off downtown, the army, led by General Eiling, rolls in and takes over the case, much to Joe's surprise. Suspicious, Joe tells Barry that he and his friends at S.T.A.R. Labs should look into the army's involvement. Wells informs the team that Eiling was experimenting on his men to turn them into super soldiers. Cisco confirms one of Eiling's soldiers, Bette Sans Souci, was at the bomb site. The Flash tracks her down and realizes that she's not setting off the bombs, she is a meta-human who can blow things up just by touching them. Meanwhile, when Joe learns Iris is writing about "the streak," he tells Barry to make her stop. Barry realizes Iris won't listen to him so he decides to have The Flash pay her a visit.

The Flash (Grant Gustin) stops a robbery but the culprits get away after shooting a guard, and The Flash chooses to save the man instead of following the criminals. Joe (Jesse L. Martin) shows Barry a book of suspects and Barry identifies Leonard Snart (guest star Wentworth Miller, “Prison Break”) as the leader of the group.

While investigating the case, Barry gets a surprise visit from an old friend — Felicity Smoak (Emily Bett Rickards, “Arrow”), who heard about his new abilities and came to check them out for herself. She joins him at S.T.A.R. Labs to help stop Snart after it’s revealed that Snart his gotten his hands on a stolen “cold gun,” which could kill The Flash. Dr. Wells (Tom Cavanagh) is furious when he finds out that Cisco (Carlos Valdes) built the cold gun without telling anyone and now it’s missing. Meanwhile, Iris (Candice Patton) is getting the silent treatment from Joe because of her relationship with Eddie (Rick Cosnett). Finally, The Flash and Captain Cold have an epic confrontation. Glen Winter directed the episode written by Goff Johns & Kai Yu Wu.

The premier of The Flash Of LifeReal Subjects...Real People, Real Life.This is the Introduction to a series of shows just to see who and what type of caller base I'll be getting.Life happens so quick; just like a flash on a camera. Show will cover a broad range of topics including but not limited to photography, religion, epilepsy, disabilities, work, health, etc...but it WILL BE REAL!